Oral cavity treatment device



FIG. 1 is a front perspective view of an oral cavity treatment device according to our new design;

FIG. 2 is a rear perspective view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a left side view thereof;

FIG. 6 is a right side view thereof;

FIG. 7 is a top view thereof; and,

FIG. 8 is a bottom view thereof.

The appearance of any portion of the oral cavity treatment device between the break lines, which are depicted by a separation and a bracket, forms no part of the claimed design. 

CLAIM The ornamental design for an oral cavity treatment device, as shown and described. 